[C320-list] Thermostat for Perkins M-30: VERY hot fresh water at sink

[Christian]

Lou,
I have a M30, and when at full load for about 30 mins, I peak at 182.  I
would be getting nervous with it edging over 200.  I suspect you have a
cooling issue somewhere, and yes I do think your very hot water at the
galley sink is related, as the engine heats your water too in the hot water
tank in addition to electrical heat.  I have also replaced my coolant
thermostat, and my high heat thermostat, and can look up part numbers if
you need assistance (but might take me about 24 hours).  Though I don't
think the high heat thermostat is your issue.

Things I would suspect in high heat are:
-check cooling system for any impeller fins or other debris
-are the tubes in your heat exchanger corroded or blocked?
-is your exhaust elbow clogged?
-Have you drained your coolant and introduced an air bubble in the system?

I would start there with those questions.  You could have an issue with
your coolant thermostat not opening, but this is not likely.  The main
failure reason of a toasted coolant thermostat is overheating the engine
and melting the wax in the thermostat (don't ask me how I know).  The good
news is it's easy to test the functionality of the thermostat, you put it
in a pot of boiling water and see if it opens.  The bad news is on the M30,
the coolant thermostat is behind your coolant pump, and a real headache to
get to (pump has to be removed, gaskets scraped, gaskets replaced, likely
seized bolts, etc).  Again, it's unlikely your coolant thermostat is your
issue, and I wouldn't focus on that yet.  Failure of that part is likely a
symptom of something else causing cooling issues on your engine, and
ultimately overheating the engine to the point of melting the wax in the
thermostat.

-Christian 1994 C320 "Canuck" #138 Monroe Harbor, Chicago, IL

On Wed, Apr 10, 2024 at 8:57 AM Louis Spitz via C320-list <
c320-list at lists.catalina320.com> wrote:

> Hi folks,
> Any thoughts on VERY hot water at galley sink, and replacing the
> Thermostat on a 1995 Perkins M-30? Could they be related? The engine runs
> HOT (c.205).
> Thanks, Lou Spitz
> Merry Chase
> #195, 1995